The invention relates to methods of fabricating substrates, in particular for use in optics, electronics or opto-electronics. To be more precise, the invention relates to methods of fabricating substrates in which an active material element is transferred onto a support.
One aspect of what is shown herein relates to a need for reducing the unit cost of such substrates in combination with obtaining a good bond between the support and the active material element of such substrates. A method of fabricating substrates may be sought, in particular for use in optics, electronics or opto-electronics, that is to include an operation of bonding an active element of a first material onto one face of a support including a second material, where the second material is less noble than the first material.
The expression “less noble” is used in this document to designate:                a material of lower crystallographic quality; in this sense, for example, an amorphous material is less noble than a polycrystalline material, which is itself less noble than a monocrystalline material; or        a material obtained by a simpler and/or faster method; according to this criterion monocrystalline silicon, for example, can be considered less noble than monocrystalline silicon carbide; note in particular that monocrystalline silicon is less costly than monocrystalline silicon carbide; or        a material of lower crystallographic quality that is also obtained by a simpler and/or faster method; for example, a material obtained by a faster drawing method usually generates comparatively more defects; a material of this kind is also usually less costly, and is considered to be less noble; or        a hybrid material including a layer or an area of material of lower crystallographic quality than the remainder, for example a monocrystalline substrate covered with a polycrystalline layer.        
A less noble material is usually less costly.
Another aspect addresses problems associated with fabricating substrates, in particular for use in optics, electronics or opto-electronics, including an operation of bonding an active material layer onto a face of a support when at least one of these two elements is polycrystalline, at least at the surface of its face intended to be bonded, and problems associated with control of polishing.